The safe operation of an elevator system is generally ensured with an overspeed governor. Overspeed governor includes a safety gear that grips the guide rail to stop an elevator car. Safety gear can be used for stopping the elevator car, counterweight or both. Safety gear is activated in an overspeed situation of the elevator car, for example.
Safety gear is linked to a governor sheave with a safety rope running via the governor sheave. Governor shave can rotate freely during normal elevator operation.
Mechanical activation means are arranged in connection with the governor sheave. Elevator car overspeed is observed when rotating speed of the governor sheave exceed a preset threshold. In that case centrifugal force causes moving of the activation means into position that locks rotation of governor sheave and therefore also movement of safety rope. This has the effect that safety gear turns into gripping position and stops movement of elevator car.